This invention relates in general to spinal fixation devices. A variety of spinal. fixation devices are known for treating scoliosis, spondylolisthesis, degenerative disc disease, vertebra fractures, and other spinal disorders or abnormalities. In many instances, such spinal fixation devices include one or more pedicle screws. A typical. pedicle screw includes a threaded shaft portion having a yoke-shaped head portion extending therefrom. The threaded shaft portion is adapted to be secured to a vertebra of the spine, while the head portion is adapted to be connected to a rod or other alignment or immobilization structure.
When used for treatment of spinal disorders or abnormalities, one or more pedicle screws are individually secured to the vertebrae of the spine to provide anchor points that can then be connected together with the rod or other alignment or immobilization structure. However, known pedicle screws do not allow movement of the pedicle screw during flexion and extension of the spine. This may create discomfort for a patient being treated using the pedicle screws.
Therefore, it would be desirable to provide a pedicle screw that allows movement of the pedicle screw during flexion and extension of the spine.